metro getting gas in oil


Old 05-06-03, 07:02 PM
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metro getting gas in oil

Hi all, this is my first post, let me just say this is an awesome board! I'm an aspiring gearhead so I've hardly read any of the other forums, but I can't wait to check them out.
Here's my question, I have a 93 geo metro, 1.0L 3 cyl engine, manual trans. It began running really rough, and not getting as much power as it did. I checked the oil and it smelled strongly like gas. I changed the oil and drove it around for about 15 minutes and it ran excellent, just like before. After parking it I took the oil cap off again and more strong gas smell. I drove it a couple of times since then and it was very rough, I don't know how to describe it, but I think it's because the engine parts aren't getting properly lubricated, either because the oil is thin or the gas is washing the oil off.
Now here's my thinking, it could be the rings letting gas enter the lower part of the engine, or a valve seal letting it get into the cam area, but it doesn't smoke at all and there would also be oil getting the cylinder in either case, right? The fact that it doesn't smoke or sputter, and ran like perfect again on fresh oil makes me think that can't be it. The fuel pump could be pumping too much gas, but it would be firing hard and misfiring and whatnot if there was too much gas getting in the cylinder.
I read something about the injector sticking on this car, pushing excess gas out after the car is off. Am I right that the 93 3 cylinder metros all had throttle body intakes, with one injector? I'm planning on putting some fuel system cleaner stuff in the tank on another fresh change of oil and just go driving around the block for a half hour or so, and see if I get the flood of gas in the oil after parking it, then replace the injector if that doesn't work. Anybody out there have any suggestions or comments? Am I on the right track?
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Old 05-07-03, 06:08 AM
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Check the fuel pressure with a reliable hand held gauge. You may have a bad fuel pressure regulator diaphragm which is letting fuel into the oil.

I believe on that, you either have to change the whole upper metering body, or the aftermarket might have a diaphragm kit for the pressure regulator.

Yes, this uses a 1.0 liter throttle body injected engine. Be careful about spending much mone on this little shoe, these are throwaway cars and not worth much.

On an old time car with a mechanical fuel pump, this condition would be a bad fuel pump. Not so on a fuel injected car. I'd lean toward a bad fuel pressure regulator.

Let us know what you find.
Old 05-07-03, 03:14 PM
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Someone early on in the ordeal had told me it was the fuel pump, but then I figured out I didn't have a mechanical fuel pump, just like you were saying. Also an auto parts store I called said the pressure regulator is part of the throttle body and you have to replace the whole unit, but the haynes manual I have is confusing on the matter. In the contents at the beginning of the fuel system chapter under fuel pressure regulator it says '1998 and later models, removal and installation' and has a section number, and that's it. But as part of the procedure to replace the fuel injector for my model, the end has instructions for how to change out the fuel pressure regulator. Mine looks just like the one they're replacing in the pictures, so I'm assuming mine is replaceable.
I'm going to take the throttle body apart probably saturday and see if I can tell if the injector is leaking gas after the car shuts off. If not I'll examine the fuel pressure regulator, and hopefully between the two I'll find the problem. By the way, anyone know how much a new injector for this model is? The thing is only an inch long, a little tiny thing, and the auto parts place I called said it was $200, but I think the guy must have been thinking of the kind where you have to replace the whole throttle body if the injector goes, b/c injectors for multiport systems are usually under $50 each...I'm gonna be doing some serious cussing if I wind up paying $200 for an inch long piece of plastic...
As far as being a throwaway car, you're probably right, but I love this little thing. I especially love the fact that it gets 50 mpg, take that iraq!! Half the reason I got it was b/c it looked really easy to work on, I've heard the whole engine without the tranny weighs under 100 lbs, hehe


edited to say I'm looking for a fuel pressure guage, have to find one you don't use a T with or whatever.
Old 05-07-03, 03:20 PM
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Yup, the TBI injector is about 200 bucks. Some of the TBI injectors are a lot of money. The whole throttle body is probably 400 bucks or so.

The regulator may not be serviceable from the OEM, but the aftermarket companies may have a replaceable diaphragm kit for it.

If you want easy to work on and safe, get an old GM rear wheel drive car .
Old 05-07-03, 04:02 PM
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Well maybe the fuel cleaner stuff will unstick the thing, I just can't believe that price.

I'm pretty sure the pressure regulator can be replace easily, in the book it has instructions to do it for, and I'll quote it b/c I think it includes my 93: metro three cylinder and 95 through 97 four cylinder models

Thanks again
Old 05-08-03, 03:55 AM
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Umm, no it won't. First thing I would do is check the fuel pressure. Rent a gauge from Autozone and follow the instructions that come with it. Then you'll know where the fault might lie.

If the injector is wasted (I don't think so), no "unsticking" will do it. The only time that "works" is when they are electrically stuck from calibration fluid, which is not the case here.

Work in order and take your time in the diagnosis, or you will spend more time and money than this little wheelbarrow could ever be worth .

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